High-speed tape-handling mechanism



Oct. 20, 1953 J. E. DE TURK ETAL HIGH-SPEED TAPE-HANDLING MECHANISM 4 sheets-Shea 1 Filed July 22, 1950 lNl/EN TORS JOHN E. De TURK ,JOHN H. MAC NEILL BY 2] T RNEY J. E. m: TURK ETAL 2,656,129 HIGH-SPEED TAPE-HANDLING MECHANISM Oct. 20, 11953 4 Sheets-Sheet 2 Filed July 22, 1950 .,S,K.U v. R e mww. N E M 00m WDM m w ak H Y @MB II-Illllullllllln llll Oct. 20, 19.53 J. E. DE TURK ETAL I 2,656,129

, HIGH-SPEED TAPE-HANDLING MECHANISM Filed July 22, 1950 4 Sheets-Sheet a nvvavm/es JOHN E. DETURK JOHN H. MACNEILL BY wi Patented Oct. 20, 1953 UNITED STAT as rarest OFFICE HIGH-SPEED i-MECHANiSM John E. De Turk, Cambridge, and John H. Maeporation of Delaware Aiiplioatibii iluly'ZZ, 1950, Serial No. 175,401

' venienuy handling long pieces of taiie lilie such a mechanism wherein any portion or the tape may be examined while moving at a desired rate of speed, and the taioe maybe started from rest and brought to rest in a minimum time, smaller than would rordinarily be permitted in view or the weight .of the spools and tape stored thereon. v

provide the foregoing and other features, the invention envisions a mechanism wherein an elongated tapa stored originally on asapmy spool having substantial mass, is passed through a mechanism of low mass on which {a certain amount of tape is removably stored over a capstan, and thence toza similar storage mechanism to a take-upspool the capstan being provided with means through which it can he rotated either direction about its axis with extraordi nar-ily ,great acceleration and deceleration. The low-mass tape-storage mechanism \efiecti-vely iso lates the capstan from the supply and take-up spools, .so that the capstan can quickly accelerate the tape to a desired speed without endangering the same physically and can make a certain amount of the tapeavailable for useat such speed during the time when the spoolsare being brought to desired supply and Stake-up speeds. The spools are bro ght to such speeds through the medium of motors which provide torques to the same, and the motors are controlled through the further med-minor ase'ns'ing device which is operated by the low-mass storage mechanism, in such a mannor that tape tension is at all times maintainers substantially constant. H k

The invention as generally described above, and the foregoing and other features thereof which ,present 1 y appear, are particularly use fu'liin the art of ldtrofiic 'computers, where it is now a practice to emplo long magnetizable tapes in cooperation with magnetic recording heads as a means "for storing information, ror examie, in acom uting machine. Accordingly, a tape, which mas he one thoiis'anti more feet long anti, tor examfil'e, made of an acetate material Glaims. (Cl; 242 -75) 2 atom; ohe hal'f inch wide and quite thin, and having powdered hiaeheti'zablo material deposited on one side thereof, is suitable for use as a stor= a e medium for magneticaily recorded informae tion. Such a tape may have, for example, a ten sile strength of five pounds, which is insufiicient if a portion of it is to be accelerated at "an ex= t-rernely high rate against the inertia of a large spool bearing the "larger portion of the taper in a particular comp ter; it is desirable to be able to examine a prescribed two inoh length or a one-thousand -foot ;tape,- and to be able to accelerate the tape With-in one-eighth of an then of linear travel from a star-id ing position to a speed of thirty inches per senor-id and further to be able to reverse the izllrection oi the tape in about three-eighths of inch from a speed in one direction of thirty inches per second to a speed in the opposite direction of sixty inches er second. It will be appreciated that these require ments would place a large strain upon a tape such as that described, having 'a tens-fie strength or only five pounds. An apparatns such as that which will be described below has been non structed which aoooniiilishes these results while imposing negligible stresses in'the tape.

Referring now to the accompanying mowing:

Fig. 1 illustrates a tape haxndling mechanism constructed accordance with the inner-mien:

Fig. 2 illustrates one in the operation of feeding tape into the slack absorber mechanism of Fig. 1:

Fig. 3 illustrates a second step of the operation illustrated Fig; 2;

Fig. '4 ill-'ustr tes schematically an alternative system for driving the tape spools in Fig; 1;;

'Fig'. 5 illustrates a control circuit for the motor of Fig. 4*; a

Fig. 6 illustrates an actual construction for sup; porting the system shown in Fig. 4,;

Fig-7 illustrates acaostan drive; and F .'8 is an enlarged view showing the details or a m ghetic crutch;

Referring now to Figs; *1,-

and 3; a 'lz rlatftnifi generally designated by the numeral 10 shears upon it a first tape spool I l; which may for convenience he termed the supply spool, and a secona tape spool 1.2, may for convenience be termed a take op s oot Each 813901 518 rdtataibly mounted upon the plane-rm to about amounting is or 14 respectively. who supply spool :lzl is driven by a first motor l5 and th'e'taikewup spool I2 is unven'by a second motor I25. The sfirst motor 1% has an armature :l I which ,iseonnected to the supply spool 1 through a shaft Mi a-m1 the second meter sl t has an armature 19 which is connected to the take-up spool 12 through .a

shaft 2|. It will be appreciated that the armatures are, in each case, directly beneath their respective spools, and the shafts are actually perpendicularly disposed with relation to the spools, but these are illustrated in a single plane in Fig. 1 for the sake of simplicity. The first and second motors I5 and I5 are provided with field windings 22 and 23, respectively, which are energized in parallel from a suitable source of D. 0., not shown, through field-current terminals 24, 25. As will be explained more in detail below, the motors provide to the spools H and I2 torques which tend to rotate them in opposite directions, as indicated by the arrow 26 and 21, respectively, shown thereon.

The platform |IJ supports also a capstan 30 which is rotatably mounted thereon and driven through a shaft 3| from a continuously running motor 32. The continuously running motor drives a first gear 33 which is meshed with a second gear 34, and each of these gears drives a magnetic clutch 35 and 36, respectively. The magnetic clutches are of a design to be described more in detail below, and may each briefly be understood to consist essentially of a constantly rotating body which is afiixed to the gear 33 or 34 and a second body, not shown in Fig. 1, which is afiixed to a shaft 3! or 38, respectively. Each of the clutches may be so operated that its shaft 31 or 38 may be caused to rotate with its constantly rotating body 35 or 36, respectively, or disengaged therefrom and stopped at will, and the construction whereby this is accomplished will likewise appear below. The shaft 31 of clutch 35 is directly connected to the cross arm 36 of a differential gear arrangement 4|. Bevel gears 42 and 43 are rotatably mounted one on each end of the cross arm 36. The shaft 38 of clutch 36 drives a gear 44 which engages another gear 45 which is rotatably disposed about the shaft 3'! of clutch 35. Thus, shaft 31 and gear 46 may be rotated coaxially in the same or opposite directions. Gear 46 is connected through a short tubular collar 4'5 to a gear 48 which is in mesh with both bevel gears 42 and 43 of the cross arm 39. A further gear 49 is in mesh with the crossarm gears 42 and 43 at the opposite sides thereof from gear 48, and completes the differential gear arrangement 4|. The shaft 3| which is connected to the capstan 36 is connected to and rotated by bevel gear 49.

It will be appreciated again that the shaft 3| is actually disposed perpendicular to the plane of the paper in Fig. 1 but is illustrated as lying in the same plane for the sake of simplicity. The capstan may be rotated in either direction by the shaft 3| by engaging one of the clutches 35 or 36 and disengaging the other clutch. Thus, assuming that the motor 32 is running continuously in a first direction in which the teeth of gear 33 which are visible appear to be moving from left to right, as indicated by the arrow 33' in Fig. 1, and the clutch 35 is energized to drive shaft 3'! while clutch 36 is de-energized and shaft 361s stationary, then the cross arm 39 is being rotated in the same direction as gear 33 while gear 45 and bevel gear 48 are stationary. Under these conditions bevel gear 49 rotates in the same direction as shaft 31 at twice the speed of shaft 31. On the other hand, if clutch 35 is de-energized, leaving shaft 31 stationary, and clutch 36 is energized, then, remembering that gear 34 is being rotated in a direction reverse to that of gear 33, gear 44 rotates in the same direction as gear 34, rotating gear 46 in the same direction as gear 33. Now, with cross arm 39 and shaft 31 stationary, and gear 46 rotating in the same direction as gear 33, bevel gear 48, through crossarm gears 42 and 43, rotates gear 49 in the same direction as gear 34. Gears 33 and 34 have the same number of teeth, and gears 44 and 46 have the same number of teeth, so that gear 49 rotates at the same speed as gear 33 or 34. All the bevel gears 42, 43, 48 and 49 of differential 4| have, of

course, the same number of teeth. Thus, gear 49, and with it shaft 3| and capstan 36, can be driven in either of two possible directions, in one of which directions the speed is double the speed of the other direction.

The tape 56 which is stored on spools H and |2 passes over the capstan 3D and is driven from one spool to the other by the capstan. As has been previously mentioned, the motors I5 and I6 rotate the spools H and I2 in opposite directions, so that, the tape being wound in opposite directions thereon, the tape is maintained under a predetermined amount of tension and can be driven frictionally by the capstan 3!] from one spool to the other. To absorb slack in the tape 56 between the capstan and each of the spools, a slack-absorber mechanism 5| is included. This mechanism includes a generally vertically disposed slack-absorber bar 52 having a plurality of rectangularly extending arms 53, 54, 55, 56, 51 and 58 mounted thereon. Arms 53, 55 and 51 extendfrom one side of bar 52, while arms 54, 56 and 58 extend from the other side thereof. The arms extending from each side are alternately arrayed along the bar, so that the uppermost arm 53, extending to the left in Fig. 1, is succeeded by the first arm 54 of those extending to the right in Fig. 1, and then by the second arm 55 of those extending from the left, etc. The material of the bar and arms is maintained at a minimum, to minimize the weight thereof, by removing excess material and leaving apertures 59 in place of the excess material. At the extreme end of each arm 53 to 58, inclusive, there IS rotatably mounted a tape-engaging pulley, the pulleys of the left-hand arms being generally designated by the reference numeral 6|, and the pulleys on the right-hand arms being generally designated by the reference numeral 62. The bar 52 is provided at its top with a cross member 63 which is of hollow tubular form and is slidably fitted over a slide bar 64. The slide bar 64 is supported at its ends in standards 65 and 66, which are mounted on the platform I0, so that the bar 52 can be slid back and forth between the standards 65 and 66 over the platform l0 w1thout substantial change in its generally vert cal direction, as shown in Fig. 1. Two additional tape-engaging pulleys 61 and 68 are rotatably mounted on the platform In in a vertical line which is displaced to the left from the line of the left-arm pulleys 6| and parallel thereto with pulley 61 intermediate the upper two leftarm pulleys GI and pulley 68 intermediate the lower two left-arm pulleys 6|. Four additional tape-engaging pulleys l6, ll, 12 and 73 are rotatably mounted on the platform 16, arrayed in a vertical line parallel to the line of the ri htarm pulley 62 and displaced to the right thereof, as shown in Fig. 1. Pulley 1| is intermediate the upper two right-arm pulleys 62, and pulley I2 is intermediate the lower two right-arm pulleys 62. The topmost and lowermost pulleys 76 and 13 of this group are idler pulleys. An additional idler pulley 14 to the left of the topmost leftearm pulley tl is also rotatably mounted on the platform .:I 0.

Assuming that tape is sbeing taken from the supply spool 11, the .tape passes first .over idler pulley '14 and then in izig-zag fashion over the topmost lett-arm pulley 61 :of the slack-absorber mechanism .51, pulley .61, intermediate left-arm pulley :61, :pulley 68, lowermost left-arm pulley 8], then around the capstan :30 to idler pulley 13, then in z-ig-bag fashion over the lowermost right-arm pulley F62 of the .slackeabsorber mechanism 5|, pulley 12 intermediate rights-arm pulley ;62, pulley :7 l, uppermost right-arm pulley 62, and then around idler pulley ill! and to the takeeup spool 12.

The tape may be threaded upon the idler mechanism .in .a simple fashion, which is illustrated Figs. 2 and 3, where the tape 56 is shown in dotted lines. Referring particularly'to Fig. 2, the bar 52 first displaced :to the left close 'to the left-hand support :65 of the .slide bar 64, so that the left-arm pulley 51 extend further to the .left in Fig. 2 than the fixed pulleys K51 and 6B. The virtue of the present construction now becomes apparent for the fixed pulleys 6! and .63 repose in Fig. 2 :between left arms ,53 and 55., and .55 and :51, respectively. With the slack-absorber mechanism in this position, the tape :50 is merely dropped or placed, Without bonding, to the right :of the left-arm pulley 6:! and simultaneously to the left of the fixed pulleys 6t and 68. Then, the s acbabsorber bar :52 is di pla ed to its extreme right-hand position, nearest the righthand support {66 of the :slide bar t l, as is illustrated in Fig. 3. Automatically, this motion creates the zig-zag engagement of the tape 56 with the pulleys 1.6!, :61 and {68, described above in connection with Fig. -1. Simultaneously, the portion of the tape :50 which is disposed between idler pulleys Fill and 13 can -now .be placed to the left of right-arm pulley 6g and to the right of .tlxed pulleys .H and .12, whereupon return of the slack-absorber 'bar -52 to the intermediate position shown in Fig. 1 provides the two zig-zag slack tape configurations in Fig. -1.

Returning .now to Fig. 1, it will be apparent that, with the tape-storage spools H and 1.2 provided with torques in opposite directions and the capstan 30 at rest, the slack-absorber mechanism :50 will tend to remain in a fixed position. As will be explained presently, the rest position of the slack-absorber bar 52 is generally half way between the extreme positions shown in Figs. 2 and 3. Upon acceleration of capstan 3!! in a .-counterclockwise direction, for example, a certain amount of tape is removed from tape-engaging pulleys 6|, It! and 68 and the same -a -nrount of tape will be provided to pulleys 62, Ill, .11, -12 and 13, causing theslack-abso-rber bar 152 to be displaced to the left in Fig. 1, thus pro- -viding effective isolation from the spools H and .12. The construction-of the apparatus shown in Fig. l is such that the slack-absorber mecha- .nism 51 has a great ,deal less inertia than the tape storage spools l I and Hand the tapestored thereon, with the result that the slack-absorber bar -52 moves long before the inertia iof the spool ll l or l2 from which tape is being taken can be overcome. Similarly, if the capstan :30 is accelerated from rest in a clockwise direction, slack tape is removed from pulleys 62, Ill, H, 12 and t and- 7s up i d to pu ler .fil. ti and. 8. c ing the slack-absorber bar 52 to move to the isle -hand res es. as is illus ra d. i Fi in. eithent sa. the tension of the .tapegtt remains substantially undisturbed. A magnetic recording or scanning head, illustrated diagrammatically at '15, may be disposed adjacent .a straight portion of the tape 50, near the capstan $80, for ex ample, and scanning of the tape for information stored thereon, or for the purpose of storing information thereon, may be commenced imme diately, without waiting for the spools I11 and 12 to be brought to full-operating speed. A sensing mechanism, generally designated as '16, cooperates with an electronic motor-control circuit, generally designated as H, for the purpose of sensing the displacement of the slack-absorber bar due to acceleration in either direction of the capstan 30, and adjusting the torques supplied between motors l5 and It to the spools I I and :I2, respectively, to restore the slack-absorber bar 52 to its intermediate, or rest, position before all the stored .slack tape has been removed from one side of it, as will now be described.

The electronic circuit 11, which controls the motors t5 and I6, comprises a transformer 80 having a primary winding 581 supplied with input terminals 82 and 83, which are adapted to be connected to a source of alternating current.

' The secondary winding :84 of the transformer 80 is connected at one end to the anode B5 .of a first grid-controlled gaseous-discharge tube 86 :and at the oth r end to the anode .8! of a second :gridcontrolled gaseous-discharge tube -88. The cathode so of the first gaseous-discharge tube is connected to one of the brushes 91 of the armature l! of the first torque motor l5, while the cathode 92 of the second gaseous-discharge tube :is connected to one of the brushes 913 of the armature IQ of the second torque motor 126. The re maining brushes 94 and :95 .of the :armatures l?! and t9, respectively, are connected together and through a common conductor 96 to the center tap '97 of the secondary winding 84. Thus, a circuit through the first armature H is completed from the center tap 9.? through the lower half of the secondary winding .84, as seen in Fig. 1, through the anode-cathode path of the first gaseous-discharge tube at to brush Bl, through the first torque-motor armature 11 and brush 94 to the common conductor 96. ,A similar circuit :for the second torque-motor armature .19 may be traced from the center tap :9] through the upper half of the secondary winding 15- 3, as seen in Fig. 1, .through the anode-cathode path of the second gaseous-discharge tube .88 to brush 93, then through the second torque-motor armature +9 to brush 95 and to the common conductor 96.

The sensing mechanism 16 is essentially an electrical phase-shifting device having input conductors llll and 1.0 2 connected, respectively, to the input terminals 82 and .83. A first capacitor I63 and a first resistor 1M are connected in series from input conductor 1 92 to input conductor Jill. A second capacitor and a second resistor we are also connected in series from in- .put conductor 1:0! to input conductor I02. A first movable tap It? on the first resistor I04 is electrically connected to the control grid [:08 of the first gaseous-discharge tube :86. A second movable tap H19 on the seccndresistor 1B6 is electrically connected to the control-grid .I ll .of the second gaseous-discharge tube 18.8. Currentlimiting resistors H2 and H3, respectively, are included in series in these connections. A first capacitor H4 is connected between the control grid I08 and the cathode 90 of the first gaseousdischarge tube 86., while a second capacitor M5 is connected between the control grid I II and the cathode 92 of the second gaseous-discharge tube 88. A fixed bias may be provided between the cathode and control grid of each of the first and second gaseous-discharge tubes 86 and 88 by fixed-bias sources H6 and III, respectively, if desired. The fixed-bias sources HE and II! may, for example, be batteries in series with suitable grid-return resistors.

The movable taps I? and III?! are mechanically affixed to the opposite ends of elongated bar I20 which is pivotally mounted at an intermediate point I2I on the platform II]. An elongated arm I22 extends rectangularly from the bar I20 at the pivot point I2 I, downwardly as shown in Fig. 1, and is provided at its lower end with a slideway I23. A pin I24, which is mounted at the upper end of the slack-absorber bar 52, is engaged in the slideway I23. As is shown in Figs. 2 and 3, the slack-absorber bar 52 is operative, through the pin I24 and the slideway I23, to retate the bar I20 bearing the taps I0? and I09 about the pivot point I2I, in a direction depending upon the direction of displacement of the slack-absorber bar from its neutral or median position, which is shown in Fig. 1. Upon rotation of bar I20 clockwise about its pivot point I2I, as is shown in Fig. 2, movable tap I07 moves along resistor I04 further away from the associated capacitor I03 and close to conductor IIlI, while movable tap I05 moves along resistor I06 closer, electrically, to the associated capacitor I05 and further away from conductor I02. This has the effect of causing one tube to fire later in its conductive half cycle and the other to fire earlier in its conductive half cycle. The sense of this change is the opposite when the bar IE0 is rotated in the counterclockwise direction, as is shown in Fig. 3. The change in either case causes one of the motors I5 or I6 to furnish more torque to its shaft I8 or 2i, respectively, and the other motor to furnish less torque to its shaft. In the case where the capstan 30 is accelerated in the counterclockwise direction, to remove tape 50 from spool I I, this change is employed to decrease the torque applied to the supply spool II in the direction of the arrow 28, and simultaneously to increase the torque applied to the take-up spool I2 in the direction of arrow 21. The sum of the torques is maintained substantially constant, so that the tension of the tape 50 will not be substantially changed. However, the difference between the individual torques is such that the slack-absorber bar 52 is returned toward its neutral or median position, shown in Fig. 1.

When the capstan 30 is accelerated in the clockwise direction, the slack-absorber bar 52 is quickly pulled toward its extreme right-hand position, as shown in Fig. 3. In this case, the firing times of the grids I08 and I I I are so altered that the torque applied to what is now the supply spool I2 in the direction of the arrow 21 is decreased, while simultaneously, the torque which is applied to what is now the take-up spool I I in the direction of arrow 25 is increased. Again, the spools are caused to feed and take up the tape 50 sufiiciently quickly to restore the slackabsorber bar 52 towards its neutral or median position.

If the capstan 30 has been accelerated to a desired speed, the slack-absorber bar 52 remains generally in its neutral or median position, and any drift away from that position is immediately sensed by the sensing mechanism It and corrected through the torque-motor control circuit TI. The tape is thus furnished at a desired constant speed, determined by the speed of the capstan 30, for scanning or recording upon by the head I5, for example. As has been pointed out above, the speed of the capstan in one direction is twice its speed in the other direction when the drive mechanism, which is illustrated in Fig. l, is employed. With a mechanism in accordance with Fig. 1, it has been found that an acceleration in excess of 10,000 inches per second may be realized while tape stress is maintained below one pound.

Referring now to Figs. 4, 5 and 6, a modifica tion of Fig. l is shown wherein an alternate spooltensioning and control system is employed to control the tape spools II and I2. In this modification, the tape spools II and I2 are shown mounted upon splined hubs I30 and I3I, respectively, which are collinearly arranged on coaxial shafts I32 and I33, respectively. It will be appreciated that the coaxial mounting of the spools I I and I2 may be employed in the embodiment of Fig. 1, also, if desired. A first or control motor I34 and a second or tension motor I35 are employed to operate this arrangement. The control motor I34 turns a shaft I36 having a pinion gear I37 at the end thereof. The pinion gear I37 is in mesh with a large idler shaft gear I38 which turns an idler shaft I39 having a second pinion gear I40 at one end thereof. The second pinion gear IIIII is in mesh with a large gear I I! which is mounted on and turns the shaft I32 on which tape spool II is mounted, and with an additional large gear Hi2 which is mounted on a hollow shaft I 33 having one bevel gear I40 of a differential Hi5 at its end. The cross arm I25 of the differential Hi5, shown in Fig. 6, is mounted on a shaft I47 which is concentrically fitted within the hollow shaft I23 and extends a distance beyond it and carries a large gear I48. The tension motor I35 turns a shaft I49, at the end of which there is mounted a pinion gear I50 which is in mesh with the last-mentioned large gear M8. The shaft m, which is turned by the tension motor I35 through gear I48 and pinion gear I50, turns the cross arm I45 of the differential I45 and with it the two cross-arm bevel gears I5I and I52. The cross-arm bevel gears are in mesh with the fourth gear I53 of the differential I45 which is mounted on a shaft I54 and turns a large gear I55. This large gear I55 is in mesh with a similar large gear I56 which is mounted on the hollow shaft I33 which carries the second tape spool I2.

As is shown in Fig. 6, shaft III is mounted at its ends at two opposite walls I58 and I59 of a rigid housing I60, and the motors I34 and I35 are mounted on the outside of wall I59. The shaft I35, which is driven by the control motor I3 3, is rotatably supported in a boss I5! which is firmly attached to wall I59, while the idler shaft I39 is also firmly supported in a portion of the base I62 of said boss. The shaft I29, which is turned by the tension motor IE5, is also rotatably supported in a second boss I63 mounted on the same base IE2 and supported firmly on the wall I59. The shafts I32 and I33 are rotatably supported in an external boss I56 which is mounted on wall I53 of the casing I60, and the splined hubs I30 and I3I project outwardly from this boss.

Referring again to Fig. 4 and assuming that the control motor turns its shaft I36 in the direction of arrow I65, which is counterclockwise in Fig. 4, then gear I38 and shaft I39 are turned clockwise the direction of arrow 166. The pinion 1.4.0 thcn causes gears MI and I42 to be turned counterclockwise in the direction of .241:- rows-IGI and I58; so that shaft I33 and spool II are turned counterclockwise the direction of arrow .159 on spool Ii. Gear I42, turning counterclockwise as shown by arrow I51, rotates bevel gear 1.44 of the differential I45 in the same direction, and, if shaft IA'I is at rest, causes gear I55; tobe rotated at the same speed in the oppo= site or clockwise direction, as shown by arrow I II, on gear I55. However, the tension motor I35 has an effect .on gear I55. Assuming that the motor is rotating shaft 549 in a clockwise di-. rection, as indicated by arrow I 72-, then the pinion gear I 5.0 thereof turns gear 148 a counterclockwise direction, as indicated by arrow 113.. The crossear-m shaft I41 then turns thecrass-arm L46 oi the .cliifercntial M5 in the counterclockwise direct-ion of arrow H13. and this causes shaft IM to. be turned in the same lirec ticn ctdonble th speed, of shaft I41. as inc cated'by arr-ow HA on gear I55. The net efiect of this is that ear I55 may be turned in either direction and, therefore, that the tape spool I2 may be turned in either direction; as indicated b @liows Hie-11d llfi-thereon,

The power for driving the motors I34 and I35 is furnished by an arrangement somewhat difier, ent than that shown in Fig. 1. The tension motor I 35 is excited by a constant voltage, from a source which. is not shown, and the torque of this motor is maintained substantially fixed. The control motor I34 is, on the other hand, con trolled both in speed and direction by a circuit similar to the control circuit 17 Fig. 1, This circuit is, however, modi ied, as is shown in 5; where similar parts to those shown the s r cnit- H of 'Fig. 1 bear like reference numerals.

The change consists essentially of placing the motor I34 in the common lead .95, which is at.- tached at one end to the center tap 3-1 of the transformer winding 84. and removing the motor armatures I! and Ithowever withoutinterrupt? ving the current paths provided thereby. 'In this manner, employing the sensing device 'IBof Fig. 1. to control'the gaseoussdischarge tubes 86 and 88'sin the same manner as in Fig. 1, the speed and direction of' the control motor I34 can be con.-

trolled.

Fig. '7 shows an actual construction for re ver'sibly driving the capstan 30, similar to the construction whichisschematica-lly shown in Fig. '1. In these two figures, like parts bear'like refer.- ence characters; In Fig. #7, however, the motor 32 drives an idier gear MI, and this gear in turn dr v s h ars 33 and 34 of the two mag etic clutches 35 and 36, respectively. The clutches are supported within a rigid casing 205 having a' generally rectangular shape. The casing has two rectan ular volumetric spaces 2.01 and 2.0.8 which are divided by a rigid partition 209. The motor 32 is mounted on the outside of a wall 295 of the casin and the idler gear 20I is disposed inside. space 201. The clutches :35 and 35 are disposed between walls 205 and 2.0.9, harallelto each other, and their output shafts 31 and so, respectively, project into space 208 on the other side of dividing partition 209. filutch 35 has .a rotatable portion 202, on which gear 33 is afiixecl, and a nonrotatable portion 2I2 which is affixed to partition 209'. Clutch .36 has a rotatable portion' 203, on which gear 34 is rigidly mounted, and a nonrotatable portion ZI3 which also affixed to partition 209,.

The rotatable portion of each clutch I is mounted on wall 205 of easing 205.105? means 01 a bolt 20.4 which supports an antifriction ball bearing 2I5 in a manner which is shown clearly on clutch 36, where the rotatable portion 203 is partly broken away. The bolt 204 has an en larged head 2I6 which cooperates with a sleeve 2I1 to compress the inner race of the ball hear: ing 2I5 between them when the nut 2 I 8 is tightened. The sleeve 2]! rests upon a boss 2 I 9 on the inside of wall 205, and a washer {MI is dis.- posed between thenut 2I8 and the outer surface of wall 205. The outer shell of rotatable member 203 has an annular groove in which a retainer ring 222 is held. An annular cap member 223 is bolted to the end of the outer shell of rotatable member 203 and retains the outer race of bali bearing 215 between the retaining ring and itself, The races are shown spaced away from their re taining members in Fig. '7 in order better to T111151:- trate the disposition of the parts. As willappear below in connection with Fig. .8, the races are. ac: tual'l-y retained tightly in their desired positions. Gear 34 is bolted to the annular cap member 223 by means of bolts 1225, being spaced therefrom by a spacer ring 226. A washer 2:21 of annular form is provided beneath the heads of the bolts 225.- It will be a preciated that th rotatable member 203 of clutch :36 is freely rotatable u on the sup ortin bolt .294 and is driv n throu h its drive ear as. The construction ofetatable member 92 of the ot ma ne ic clutch is ice tioet Dis osed be ween fixed and r t-sta e mem er f each clu ch is a cl tch d sh 30 which can a netica y a racted to cithc mombor as will p ese tly he exp ai ed in connec ion with Fi ii Th clu ch d sk is afiixed to t e shaft 7 r .33 of its clu ch rns the same wh n it s in ontact with the ot ta e member of the clutch and ho s the amcstat cna y when it is in ntact w th the .fixcd, mem r o he clutc ha 3'! one 3- driv r sp c ve y, the ross .39 of difi rentio a d ear 44. ,An id er ear 23 is included be -we n se rs 4 and 46 be cause of the in lusion o idl r gear 2.0! be n lutch gea s 33 Th differential gear is, instead o dr ing dire tly he shaft 3!. as t does in Fig. 1, drives a gear 232, which in turn drives another gear 3 n'the sh ft o the capst 3!! It will c rpr ciat d that the arrangement sho Fig, ope ates substantially i the ame manne Fisto driv he aps an n e the of its t o possib e di c ons.- a

Refer ing now o igth on u t on o he mag eti clu ches. is ho n in d ail- The efer nce ume als cor pond t refe nc no: mor s of clut h :36.- The ro ata le membe .2 an outer shol t 3 in which the re ainer rin 222 s uppo ted- Ihc head 2 I6 of bo t 2"! beers he i ner r ce o ba l bearin 215.. A plural ty of shims 236 may be provid d suitab y-to adinst t comp ssion eff c d on th nn r ra when th bo t is t gh en d.- A shoe 2. of an nu ar orm wh h 'frict ona y ngag he clutch disk i threaded on he out sh l 2.35- .A fi st maen t zeblo p ce 238 is cfiixedxasby wel in a ou 2. 9 t the h ad i fi of. olt 4 a coop ratin macn izohlc pie 249 s retained on the fi st p ece 23 by a reta ner ri g 24! which his int inte na an ular oove 2. 2 the coop ratin pie e and. over an edge of the first maenet-izable piece .238. An annular channel 243 is retained between the two magnetizable pieces 1238 and240, and a coil 244 is wound in this channel. Wires 24.5, 245. pass through a passage 241 in the first magnetizable piece 238, and a cooperating passage 248 in the bolt 264, which is hollow, to the exterior of the clutch. The wires are in a fixed portion of the clutch, and, therefore, no rotation thereof will be encountered. The two magnetizable pieces 23B and 240 have pole surfaces 250 and 25! which are separated by a'resilient ring 252.

The shaft 38 holds the clutch disk 230 splined thereon, so that the disk is slidable a short distance along the axis of the shaft, and the end of the shaft within the clutch is mounted in a recess 253 within the first magnetizable member 236. When the coil 244 of the rotatable member 263 is energized, the clutch disk 23!], which is also made of magnetizable material, is attracted to the poles 250 and 25!. The disk is provided with a first annular friction member 254, however, which engages the confronting surface 255 of the shoe 231 just prior to the disk 236 coming in contact with the poles 250 and 25L In this manner, the clutch disk is caused to rotate when the rotatable member 203, more particularly the outer shell 235, is rotated.

The fixed member 2|3 of the clutch is affixed to partition 209 by bolts 256. An outer mag netizable piece 251, of generally tubular form, has an outwardly-projecting flange 258 which threadedly engages the bolts 256. An inner magnetizable member, also of generally tubular shape, has an outwardly-projecting flange 260 through which the bolts 256 pass, which is compressed between the flange 258 of the outer magnetizable member and the partition 209 when the bolts are tightened. A generally annular channel member 26| is supported between the magnetizable members 251 and 259, and a coil '262 is disposed therein. Wires 263 and 264 are disposed in a passageway 265 through the inner magnetizable member 259 and a passageway 266 in partition 209. The magnetizable members 251 and 259 are, respectively, provided with pole surfaces 261 and 268 of annular form like the pole surfaces 256 and 25l of the rotatable member. Again, a resilient annulus 269 is retained between the poles. A shoe member 21l threadedly engages and fits over the outer magnetizable member 251.

Whenthe coil 262 of the fixed clutch member is energized, the clutch disk 236 is attracted to the pole surfaces 261 and 268 thereof. The clutch disk is provided, however, with a second annular friction member, on the opposite side thereof from the first such member 254, and engages the confronting surface 213 of the shoe member 21! before the disk 230 itself can come in contact with the pole pieces 261 and 268. This effectively holds the shaft 38 rigid and nonrotatable when the fixed-member coil 262 is energized. When neither coil is energized, the shaft 38 is freely rotatable.

The arrangement of the hubs II and I2 collinearly, as shown in Fig. 4, contributes greatly to the ease with which the apparatus can be used. The splined hubs I30 and I31, shown in Fig. 6, are conveniently provided with identical splines and, in a manner well known in the art, with spring detents (not shown), so that the spools H and I2 may be of identical design, and may be simultaneously slipped over the hubs or removed from the same. In this manner, hearing in mind thatthe threading of the present apparatus is extremely simple and can be done with unlooped tape, a length of tape, which is disposed partially on one spool and partially on l 2. the other, may be removed from or placed upon the mechanism with a minimum of effort at any time.

It will be appreciated by those skilled in the art that the foregoing detailed desriptions of particular means for carrying out the invention are exemplary only and that other modifications of the invention are possible. Accordingly, it is intended that the claims which follow shall not be limited by these details, which are illustratory only.

What is claimed is:

1. Tape-handling mechanism comprising a. base, a first set of tape-engaging spools mounted in a first row on said base, a second set of tapeengaging spools mounted on said base in a second row parallel to said first row, a secondary base member having an elongated portion and a plurality of arms mounted thereon and extending alternately from opposite sides and substantially perpendicularly therefrom in a common plane, a tape-engaging spool mounted on each of said arms, and means on said base movably supporting said secondary base member with said elongated portion between and substantially parallel to said rows. 6

2. Tape-handling mechanism comprising a plane base, a first set of tape-engaging spools mounted in spaced-apart relation in a first row on said base, a second set of tape-engaging spools mounted in spaced-apart relation on said base in a second row parallel to said first row, a secondary base member having an elongated portion and arms mounted thereon and extending alternately from opposite sides and substantially perpendicularly therefrom in a common plane, a tape-engaging spool mountedon each of said arms, and means on said base movably supporting said secondary base member with said elongated portion between and substantially parallel to said rows and said common plane parallel to the plane of said base, the arms on one side of said elongated portion being disposed to extend between the spools of said first set when said elongated portion is displaced to be closely adjacent to said first row, and the arms on the other side of said elongated member being disposed to extend between the spools of said second set when said elongated member is displaced to be closely adjacent to said second row.

3. Mechanism in accordance with claim 2 wherein said mounting means comprises a tubular member mounted at one end of said elongated portion and disposed perpendicular thereto, an elongated bar slidably fitted within said tubular member, and mean on said base supporting said bar parallel to said base and perpendicular to said rows.

4. Tape-handling mechanism comprising a plane base, a first set of tape-engaging spools mounted in spaced-apart relationship on said base, a second set of tape-engaging spools mounted in spaced-apart relationship on said base and separated from said first set, a secondary base member having an elongated portion and a plurality of arms mounted thereon and extending alternately from opposite sides and substantially perpendicularly therefrom in a common plane, a third set of tape-engaging spools mounted on said arms of the secondary base member, means on said base movably supporting said secondary base member with said third set between said first and second sets of spools, a tape supply spool and a tape take-up spool both mounted on said base, means to procud ing said secondary base member with said third set between said first and second sets of spools, a tape-supply spool and a tape takeup spool both mounted on said base, means to provide torque to each of said supply and take-up spools, and means responsive to the displacement of said secondary base memher from a prescribed position with relation to said base to alter said torques in opposite senses.

11. Tape-handling mechanism comprising a base, a first set of tape-engaging spools mounted in a first row on said base, a second set of tapeengaging spools mounted on said base in a second row parallel to said first row and separated from said first set, a secondary base member having an elongated portion and a plurality of substantially perpendicularly extending arms mounted thereon, a third set of tape-engaging spools each mounted on an arm of said secondary base member, means on said base movably supporting said secondary base member with said third set between said first and second set of spools, a tape-supply spool and a tape take-up spool both mounted on said base, electric motor means to provide torque to each of said supply and take-up spools, and means having relatively movable members mounted in part on said base and in part on said secondary base member and responsive to the displacement of said secondary base member from a prescribed position with respect to said base to cause said motor means to alter said torques in opposite senses.

12. Tape-handling mechanism comp-rising a base, a first set of tape-engaging spools mounted in a first row on said base, a second set of tapeengaging spools mounted on said base in a second row parallel to said first row and separated from said first set, a secondary base member having an elongated portion and a plurality of substantially perpendicularly extending arms mounted thereon, a third set of tape-engaging spools each mounted on an arm of said secondary base member, means on said base movably supporting said secondary base member with said third set between said first and second sets of spools, a tape-supply spool and a tape takeup spool both mounted on said base, means to provide torque to each of said supply and takeup spools, means responsive to the displacement of said secondary base member from a prescribed position with relation to said base to alter said torques in opposite senses, a capstan mounted on said base for driving tape between said supply and take-up spools, and means for rotating said capstan.

13. Tape-handling mechanism comprising a base, a first set of tape-engaging spools mounted in a first row on said base, a second set of tape engaging spools mounted on said base in a second row parallel to said first row and separated from said first set, a secondary base member having an elongated portion and a plurality of substantially perpendicularly extending arms mounted thereon, a third set of tape-engaging spools each mounted on an arm of said secondary base member, means on said base movably supporting said secondary base member with said third set between said first and second sets of spools, a tape-supply spool and. a tape takeup spool both mounted on said base, means to provide torque to each of said supply and takeup spools, means responsive to the displacement of said secondary base member from a, prescribed position with relation to said base to alter said torque in opposite senses, a capstan mounted on said base for driving tape between said supply and take-up spools, means for rotating said capstan, and means for substantially instantaneously reversing the direction of rotation of said capstan.

14. Tape-handling mechanism according to claim 13 in which the capstan reversing means comprises first and second clutches each having a constantly rotating body and a nonrotating body, the nonrotating body having a longitudinal passage therethrough collinear with the axis of rotation of the rotating body, a shaft rotatably supported in said passage, and a clutch disk splined on the shaft movable between said bodies, said clutch disk being made of magnetizable material and the rotating and nonrotating bodies each having electromagnetic means to attract and hold the clutch disk, and clutch facings on the disk and each body of each clutch, means simultaneously to energize the electromagnetic means of the rotating body of one of said clutches and the electromagnetic mean of the nonrotating body of the other of said clutches, and a driving connection between the shaft of each clutch and said capstan, said connections being arranged for driving said capstan in opposite directions from said constantly rotating bodies.

15. Tape-handling mechanism comprising a tape-supply spool, a tape take-up spool, a tape path extending between said means, a capstan, first slack-absorber means positioned in said tape path between said capstan and said supply means, said first slack-absorber means comprising a first tape-engaging spool with its axis of rotation movable with respect to the said supply means, second slack-absorber means positioned in said tape path between said capstan and said take-11p means, said second absorber means comprising a second tape-engaging spool with its axis of rotation movable with respect to said takeup means, means to efiect a fixed relation between the displacements of the movable tapeengaging spools of the first and second slackabsorber means with respect to said supply and take-up means, driving means for said supply and take-up spools comprising first and second Coaxial shafts, first and second hubs supported collinearly by said first and second shafts, respectively, and means to provide torque to each of said shafts, and means responsive to the displacement of said movable tape-engaging spools of said slack-absorber means with respect to said supply and take-up means to alter said torque in opposite senses.

JOHN E. DE TURK. JOHN H. MACNEILL.

References Cited in the file of this patent UNITED STATES PATENTS Number Name 1,422,359 Hill July 1 l 1922 1,848,663 Robinson, Jr Mar. 3 1932 1,940,702 Shope Dec. 26 1933 2,363,684 Montgomery Nov. 28 1944 2,459,617 Carter Jan. 18 1949 2,542,917 Fischer et al Feb. 20 1951 2,560,204 Andren July 10 1951 2,576,074 Nachtman Nov. 20: 1951 FOREIGN PATENTS Number Country 425,399 France Ap i lilll 10,011 Great Britain Apr. 27: 1912 

